During substrate processing, such as etching process, an inner volume of a process chamber may be exposed to one or more process gases. Often, such processing is performed at a controlled pressure. Pressure gauges may be used to monitor the pressure in the inner volume. Currently, a reference pressure gauge is used to approximately calibrate the pressure gauge to a zero point. Unfortunately, such calibration is typically provides an accuracy of about +/−15% or so. The inventors have observed that there is typically no on-tool apparatus available on a multi-chamber substrate processing system, such as a cluster tool, for checking the pressure gauges of each chamber for drift or for comparing drift between pressure gauges on adjacent chambers of the system. In addition, the inventors have further observed that no practical external devices are available to perform this calibration task in a timely manner.
Accordingly, the inventors have provided a system and methods disclosed herein for calibrating pressure gauges in one or more process chambers of a multi-chamber substrate processing system.